The present invention relates to container closures, and more particularly, to a low profile over-center toggle latch.
Low silhouette adjustable latches are known in the art for use in providing adjustable latching of container closure members. In U.S. Pat. No. 4,243,255, a tension latch, embodying an over-center latching principle, includes means for adjusting the latch tension in the fully closed and latched position. The adjustment means is readily accessible through a channel-like opening formed by the latch handle. This latch handle portion contains a secondary locking mechanism which is laterally offset from the adjustment means. The locking mechanism is activated from the side of the handle for tension adjustment. However, such low silhouette arrangement is relatively complex and requires a multiplicity of cooperating elements.
In U.S. Pat. No. 3,127,205, an under-center toggle latch is disclosed for securing together cooperating members of a container. This latch comprises a sheet metal angle bracket mounted to a first member of the container and an operating handle, where a primary lever of channeled construction is mounted between sidewalls of the abovesaid bracket by means of spaced, an axially aligned pivot pin which passes through aligned hollows of the handle. The draw hook-tension bar assembly includes a hook section and a threaded rear terminal or shank section. The draw hook is mounted in a tension bar element which may be formed from a single elongated blank bent double and is provided at its center with a hinge pin loop and overlapping flanges. These flanges may be welded together and provided with complimentary outwardly curved radial sections for forming an opening which is internally threaded to receive the shank of the draw hook in a readily adjustable relation. This threaded sleeve section has slots to indicate the position of the threaded shank section of the draw hook. The pivot element is mounted on a pivot pin positioned in aligned openings at the inner end of sidewalls of the primary lever. The draw hook at its outer end engages a hook shaped keeper mounted on the second member of the closure. The hook section may be rotated to adjust the operative tension of the draw hook in a closed position. In order to engage the draw hook for closure of the container, the draw hook is mated with the hook shaped keeper while the primary lever is rotated in direction of the hook shaped keeper, such that the primary lever is rotated about the pivot pin and is brought to abut and overlay the hook section. A major problem with such arrangement, however, is that the toggle latch of this arrangement requires a relatively high profile and has the drawbacks inherent in such under-center configuration.
Furthermore, in both of the above-described arrangements the primary lever of the latch can be jostled during operation of the latching mechanism which can cause unwanted releasing thereof, or can result in damage to the latching mechanism. As well, an unprotected mechanism can present a dangerous obstruction to passers-by.